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Tank Slappers

1hotrn

1hotrn

New member
Joined
Aug 19, 2003
Location
Fremont
Moto(s)
2003 NINJA ZX-6R
Hello,
I experieced today on 680 going about a hunsky my handle bars skaking back and forth on their own. I was wondering if someone could explain this phenomenon also know as the "Tank Slapper". It scared the poopie out of me:jaded . I think I my front tire hit a raised bump in the road while I was getting on the throttle.
 
You experienced a bit of wobble, not a tank slapper. A tank slapper is when the steering goes full lock and you're not likely to recover from it at speed. I had the privilege of experiencing a tank slapper firsthand a little over a year ago, and I don't ever want to go through that again. I didn't get much time to "enjoy it" before I got tossed off.

Things to check: tires, steering head bearings, frame geometry.

You might want to consider adding a steering damper.
 
When the front end get light, usually under acceleration, and then you go over something that upsets the front end (slight bumps etc.), you'll sometimes encounter "headshake". Ease off the throttle and that will usually calm the front end down.

Tank slappers, like the above post states, are something that will usally end up in a crash. Think of the "headshake" at high speed.
 
yes, headshake is bars moving, tankslapper is when you see the bars whack the tank a couple times and then the guy behind you sees you upside down ten feet in the air.
 
you forgot to add "ten feet in the air, your eyes wide open, mouth open in a rictus of terror as you realize... gravity works all the time." :laughing

a good steering damper will help you alleviate/avoid the headshake/tankslapper situations.
 
Also, check your suspension settings. I may be wrong
but I think that too much rebound damping in the front
can increase the likelyhood of a headshake. (it did in my case,
also on 680, goin around a turn at 70 mph, also scarred the
poopie out of me.) I backed off the damping and it hasn't happened since. I could be wrong, if I am, please somebody
correct me...

(off topic, 1hotrn, do you work at Washington Hospital? My wife is due to have our baby in late Dec. and we are gonna go there...)
 
All that said, hitting a bump while hard on the throttle is more than enough to get the front end loose on an aggressive geometry bike like the 636.
 
afm199 said:
yes, headshake is bars moving, tankslapper is when you see the bars whack the tank a couple times and then the guy behind you sees you upside down ten feet in the air.
Click to expand...


When you see your bike moving it's own bars back and forth from stop to stop and realise that you're viewing this from a point of view three feet in front of the bike, two feet up, you're inverted and you're facing the direction you just came from, that's a tankslapper.

Amazing how time j u s t s e e m s t o s l o w d o w n during a tankslapper.

It's usually all over inside a second, but it doesn't feel like it.
 
You're on a 6R. Start getting used to them!

Actually, a steering dampener is a must have for that bike. Allot of us like the GPR product, immensely!

I'd add one on that bike as the first mod. It really should have come with one...
 
Frame geometry is very complex and the headshake you describe can be caused by several factors all working together. The fork oil that comes from Japan is incredibly average. Combine that with possible low tire pressure and a ripple in the pavement and you get a big surprise. Headshake can turn into a tankslapper faster than you can poop your pants, especially if you overreact. Proper suspension settings for your style/weight etc. are critical. Is this a one time thing or does it happen frequently?
 
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My last tankslapper the guy behind me said I was suddenly 12 feet up in the air upside down. I hit the asphalt, left a gouge in it, and tumbled 129 feet into the ditch, where I came to listening to Henrik say: "I'll go get the Ambulance."

Oh, did I mention how incredibly violent it is?

:)
 
Dampers work great, but just don't bolt one on without checking the basics first. If your suspension isn't adjusted right, you have low tire pressure, worn tires, loose stem bearings, a misaligned rear wheel, bad wheel bearings or loose motor mounts the damper is just a band aid. There's a lot to check. Also, the chassis adjustability is great if you use it properly. But if it's set up wrong it can cause major problems.
 
Can't stress enough that a properly set up suspension is a must. Lots of people buy their bikes and don't adjust the suspension, and then complain that the bike rides like ass. Do yourself a favor: get your suspension dialed in for *YOU*, and then get a steering damper (GPR, Scott's, Ohlins). Save yourself the hassle and the possible accident.
 
afm199 said:
Oh, did I mention how incredibly violent it is?
Click to expand...
"Incredibly violent" is an excellent way to describe a tank slapper.

Thump mentioned about time seeming to slow down. My experience with a small number of car and motorcycle wrecks is that either time seems to slow down as the adrenaline kicks in and you find you can't quite avoid crashing, or it's all over so quickly that you may not be sure what happened. The last time I wrecked a car it was the slow motion thing. When the Ducati Monster did the tank slapper, it was quick. One second I'm realizing I'll be crashing and the next I'm getting up off of the road trying to figure out what just happened. I had just enough time to think "Oh no! I'm going to crash!"
 
Well all I have to ad is that if you do experience a true lock to lock tankslapper and keep it on two make sure to pump your front brakes back up. With floating discs the rotors can slap the brake pads away. You need two-three pumps on the lever to get your brakes back.
 
My last major car accident was the slow motion thing, involving a mid air 360 degree rollover, landing on the passenger-side of the roof before completing the roll to land on all 4 tires. I could recall EVERY SINGLE MOMENT of the entire ordeal. What seemed like ages to me in reality only lasted about 3 seconds.
 
kiltwearinfool said:
Heh, I guess we'll have to start referring to Corb as "Cowboy Corb", because he rides 'em out :laughing
Click to expand...

Yea, I did learn that trick the scarry way :teeth
 
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